Air Pump with Low Pressure Gauge Protective Device

ABSTRACT

An air pump includes a inflating device, a pressure gauge, and a protective device. The inflating device includes a base, an inlet portion, a detection portion, and an outlet portion. The pressure gauge is mounted on the detection portion. A passage is interconnected with the inlet, detection and outlet portions. The protective device is disposed in the passage and includes a body and a sliding member. The body includes a slot and a hole. The sliding member inserts into the slot and is movable relative to the base to adjust a gap size between the base and the body for controlling air flow pressure in an affordable range of the pressure gauge.

BACKGROUND

The present invention relates to an air pump and, in particular, to an air pump including a low pressure gauge protective device.

China Patent No. 102562517 discloses an inflator embedded with a pressure gage, which includes a base with a hole, a hose connected to the base, a cylinder jointed to the hole, a piston rod movable in the cylinder to enable the hose to output pressurized air, and a pressure gage installed in the cylinder.

However, the inflation pressure of bicycle tires ranges from below 30 PSI (2 BAR; 207 KPA) for tubeless mountain bike tires to 220 PSI (15 BAR; 1,517 KPA) for tubular track racing tires. The aforementioned air pump cannot accurately and precisely measure and indicate the lower pressure bike tires, which are often used on mountain bikes and for riding in snow.

Therefore, if the aforementioned air pump replaces a pressure gage with a lower pressure measurement upper limit value for measuring the lower pressure bike tires, the excessive pressurized air will violently flow into the pressure gage to damage the pressure gage during pumping operations.

Thus, a need exists for a novel air pump with easily recognizable size indicia to mitigate and/or obviate the above disadvantages.

BRIEF SUMMARY

According to the present invention, the main purpose is to provide an air pump includes an inflating device, a pressure gauge, and a protective device. The inflating device includes a base, a cylinder, a piston rod, an inlet portion, a detection portion, and an outlet portion. The cylinder is connected to the base. The piston rod is slidably disposed inside the cylinder. The inlet portion is arranged at the base and engaged with the cylinder. A passage is arranged at the base and includes a first section, a second section, and third section interconnected with each other. The first section is interconnected with the inlet portion. The second section is interconnected with the detection portion. The third section interconnected with the outlet portion. The pressure gauge is mounted on the detection portion. The protective device is disposed in the passage and includes a body and a sliding member. An outer periphery of the body is airtightly abutted against an inner periphery of the passage. The body includes first and second ends spaced from each other, a slot, and a hole. The first end of the body is located adjacent to the inlet portion. The slot extends from the first end of the body to the second end of the body. The hole is located between the first and second ends of the body and interconnected with the slot and the inlet portion. The sliding member includes first and second ends spaced from each other, a wide section, and a narrow section. The first end of the sliding member inserts into the slot via the first end of the body. The first end of the sliding member is located between the hole and the second end of the body and airtightly abutted against an inner periphery of the slot. The second end of the sliding member protrudes out of the slot and forms the wide section. A width of the wide section is not less than a width of the slot. The narrow section is located between first and second ends of the sliding member. A width of the narrow section is less than the width of the slot.

An advantage of the air pump according to the present invention is that the sliding member is movable relative to the base to adjust a gap size between the base and the body for controlling air flow pressure in an affordable range of the pressure gauge.

Illustrative embodiments will become clearer in light of the following detailed description described in connection with the drawings.

DESCRIPTION OF THE DRAWINGS

The illustrative embodiments may best be described by reference to the accompanying drawings where:

FIG. 1 is a perspective view of an air pump of a first embodiment according to the present invention.

FIG. 2 is a partial, exploded perspective view of the air pump of FIG. 1.

FIG. 3 is a partial, enlarged cross sectional view of the air pump of FIG. 1.

FIG. 4 is a continued view of the air pump of FIG. 3 and illustrates a piston rod moving forth inside a cylinder to push air to pass through a manifold and a protective device.

FIG. 5 is a partial, enlarged view of the air pump of FIG. 4 and illustrates the pressurized air flowing through the protective device.

FIG. 6 is a partial, top view of the air pump of FIG. 1 and illustrates a pressure gauge indicating the pressure value while the piston rod pushing air.

FIG. 7 is a continued view of the air pump of FIG. 4 and illustrates the piston rod moving back inside the cylinder to draw in air from outside.

FIG. 8 is a partial, top view of the air pump of FIG. 1 and illustrates the pressure gauge indicating the pressure value while the piston rod drawing air from outside.

FIG. 9 is a partial, enlarged cross sectional view of an air pump of a second embodiment according to the present invention.

FIG. 10 is a continued view of the air pump of FIG. 9 and illustrates a piston rod moving forth inside a cylinder to push air to pass through a manifold and a protective device.

FIG. 11 is a partial, enlarged view of the air pump of FIG. 10 and illustrates the pressurized air flowing through a protective device.

FIG. 12 is a continued view of the air pump of FIG. 10 and illustrates the piston rod moving back inside the cylinder to draw in air from outside.

FIG. 13 is a perspective view of an air pump of a third embodiment according to the present invention.

FIG. 14 is a partial, exploded perspective view of the air pump of FIG. 13.

FIG. 15 is a partial, cross sectional view of the air pump of FIG. 13.

FIG. 16 is a continued view of the air pump of FIG. 15 and illustrates a piston rod moving forth inside a cylinder to push air to pass through a manifold and a protective device.

FIG. 17 is a partial, enlarged view of the air pump of FIG. 16.

FIG. 18 is a continued view of the air pump of FIG. 16 and illustrates the piston rod moving back inside the cylinder to draw in air from outside.

All figures are drawn for ease of explanation of the basic teachings only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the illustrative embodiments will be explained or will be within the skill of the art after the following teachings have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings have been read and understood.

Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “first”, “second”, “side”, “end”, “portion”, “spacing”, and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the illustrative embodiments.

DETAILED DESCRIPTION

FIGS. 1-8 show an air pump 10 of a first embodiment according to the present invention. The air pump 10 includes an inflating device 20, a pressure gauge 30, and a protective device 40.

The inflating device 20 includes a base 21, a cylinder 22, a piston rod 23, a recess 24, an inlet portion 25, a detection portion 26, an outlet portion 27, and a manifold 28. The base 21 includes a bottom surface 211 and a top surface 212 spaced from each other. The bottom surface 211 is adapted to be seated on the ground. An end of the cylinder 22 is connected to the base 21. The piston rod 23 is slidably disposed inside the cylinder 22 and connected with a piston for pushing air. The recess 24 is formed in the base 21 and extends from the bottom surface 211 to the top surface 212. The inlet portion 25 and the detection portion 26 are respectively disposed on two opposite ends of the top surface 212 of the base 21 and intercommunicated with the recess 24. The inlet portion 25 is arranged at the base 21 and engaged with the cylinder 22. The outlet portion 27 is disposed between the inlet portion 25 and the detection portion 26 on the top surface 212 of the base 21 and interconnected with the recess 24. The outlet portion 27 is connected to a hose 271, and an end of the hose 271 opposite to the outlet portion 27 is connected to a nozzle 272 adapted for engaging a tire of bike for inflating. The manifold 28 is mounted in the recess 24 and forms a passage 281 linearly extending therethrough. The passage 281 is arranged at the base 21 and includes a first section 282, a second section 283, and third section 284 interconnected with each other. The first section 282 is interconnected with the inlet portion 25. The second section 283 is interconnected with the detection portion 26. The third section 284 is interconnected with the outlet portion 27.

The pressure gauge 30 is mounted on the base 21. Preferably, the pressure gauge 30 is mounted on the detection portion 26 and displayed on the top surface 212. In the embodiment, a pressure measurement upper limit value of the pressure gauge 30 is less than 30 PSI.

The protective device 40 disposed in the passage 281 and received in the detection portion 26. The protective device 40 includes a body 41, a sliding member 42, a stopper 43, and a guiding member 44.

An outer periphery of the body 41 is airtightly abutted against an inner periphery of the passage 281. The body 41 includes first and second ends 411 and 412 spaced from each other, a slot 413, and a hole 414. The first end 411 of the body 41 is located adjacent to the inlet portion 25. The slot 413 extends from the first end 411 to the second end 412. The hole 414 is located between the first and second ends 411 and 412 and interconnected with the slot 413 and the inlet portion 25. Moreover, the hole 414 is interconnected to an air inlet port of the pressure gauge 30.

The sliding member 42 includes first and second ends 421 and 422 spaced from each other, a wide section 423, and a narrow section 424. The first end 421 of the sliding member 42 inserts into the slot 413 via the first end 411 of the body 41, and is located between the hole 414 and the second end 412 of the body, 41 to airtightly abut against an inner periphery of the slot 413. The second end 422 of the sliding member 42 protrudes out of the slot 413 and forms the wide section 423. Preferably, a width of the wide section 423 is not less than a width of the slot 413. The narrow section 424 is located between first and second ends 421 and 422 of the sliding member 42. Preferably, a width of the narrow section 424 is less than the width of the slot 413. The sliding member 42 is movable relative to the base 21 to adjust a gap size between the base 21 and the body 41.

The stopper 43 is located at the second end 412 of the body 41 and threadly engaged in the slot 413 to seal a side of the slot 413 adjacent to the second end 412 of the body 41. Moreover, the stopper 43 is rotatable to synchronously move in the slot 413 along an axis of the body 41.

The guiding member 44 is disposed in the passage 281 and faces to the wide section 423 of the sliding member 42.

The guiding member 44 includes a plurality of retaining walls 441 abutted against the inner periphery of the passage 281. Furthermore, every two of the retaining walls 441 form a channel 442 linearly extending therethrough.

A user can push the piston rod 23 to move forth inside the cylinder 22 to push air. Hence, the pressurized air passes through the passage 281 and is rectified by the plurality of channels 442 of the guiding member 44. A part of the pressurized air flowing into the third section 284 passes through the hose 271 and the nozzle 272 into to a tire (not shown).

Another part of the pressurized air flowing towards the wide section 423 of the sliding member 42 pushes against the wide section 423 of the sliding member 42 to cause the sliding member 42 moving relative to the body 41 to reduce the gap size to control air flow. Then, the pressurized air passing through the hole 414 into the pressure gauge 30 is measured.

The sliding member 42 is movable relative to the base 21 to adjust the gap size between the base 21 and the body 41 to prevent the excessive pressurized air violently to damage the pressure gage 30 during pumping operations.

Moreover, when the piston rod 23 is moved forth inside the cylinder 22 to push air, the air pressure value measured by the pressure gage 30 is inaccuracy to overestimate the actual air pressure value at this moment. When the piston rod 23 is moved back inside the cylinder 22, air will still flow through the a gap formed between the base 21 and the body 41 to balance the air pressure in the pressure gauge 30 and the passage 281 to obtain an accurate air pressure value measured by the pressure gage 30.

FIGS. 9-12 show an air pump in accordance with a second embodiment of the present invention. The second embodiment is generally similar to the first embodiment except that the protective device 40 a further includes a biasing member 45 a arranged between the sliding member 42 a and the stopper 43 a. Two opposite ends of the biasing member 45 a respectively bias against the sliding member 42 a and the stopper 43 a. In this embodiment, the biasing member 45 a is a spiral spring.

When the pressurized air pushes against the sliding member 42 a, the biasing member 45 a also biases against the sliding member 42 a to keep the gap having an appropriate size to protect the pressure gauge 30 and to prevent the air flow rate too low. Additionally, the stopper 43 a is movable with respect to the body 41 a to adjust the biasing force value produce by the biasing member 45 a.

FIGS. 13-15 show an air pump 10 b in accordance with a third embodiment of the present invention. The third embodiment is generally similar to the first embodiment except that the pressure gauge 30 b is engaged in an adapting portion 31 b, and a bottom of the adapting portion 31 b is connected to an extension tube 32 b configured to connected with the base 21 b. The protective device 40 b is received in the extension tube 32 b. Moreover, a side of the adapting portion 31 b is connected with a holding portion 33 b arranged around a periphery of the cylinder 22 b.

Although specific embodiments have been illustrated and described, numerous modifications and variations are still possible without departing from the scope of the invention. The scope of the invention is limited by the accompanying claims. 

1. An air pump comprising: an inflating device including a base, a cylinder, a piston rod, an inlet portion, a detection portion, and an outlet portion, with an end of the cylinder connected to the base, with the piston rod slidably disposed inside the cylinder, with the inlet portion arranged at the base and engaged with the cylinder, with a passage arranged at the base and including a first section, a second section, and third section interconnected with each other, with the first section interconnected with the inlet portion, with the second section interconnected with the detection portion, with the third section interconnected with the outlet portion; a pressure gauge mounted on the detection portion; and a protective device disposed in the passage and including a body and a sliding member, with an outer periphery of the body airtightly abutted against an inner periphery of the passage, with the body including first and second ends spaced from each other, a slot, and a hole, with the first end of the body located adjacent to the inlet portion, with the slot extending from the first end of the body to the second end of the body, with the hole located between the first and second ends of the body and interconnected with the slot and the inlet portion, with the sliding member including first and second ends spaced from each other, a wide section, and a narrow section, with the first end of the sliding member inserting into the slot via the first end of the body, with the first end of the sliding member located between the hole and the second end of the body and airtightly abutted against an inner periphery of the slot, with the second end of the sliding member protruding out of the slot and forming the wide section, with a width of the wide section not less than a width of the slot, with the narrow section located between first and second ends of the sliding member, with a width of the narrow section less than the width of the slot.
 2. The air pump as claimed in claim 1, with the protective device further including a stopper and a biasing member, with the stopper located at the second end of the body and threadly engaged in the slot to seal a side of the slot adjacent to the second end of the body, with the stopper rotatable to synchronously move in the slot along an axis of the body, with the biasing member arranged between the sliding member and the stopper, and with two opposite ends of the biasing member respectively biasing against the sliding member and the stopper to push the sliding member moving away from the stopper.
 3. The air pump as claimed in claim 2, wherein the biasing member is a spiral spring.
 4. The air pump as claimed in claim 2, with the protective device further including a guiding member disposed in the passage and facing to the wide section of the sliding member, with the guiding member including a plurality of retaining walls abutted against the inner periphery of the passage, and with every two of the retaining walls forming a channel linearly extending therethrough.
 5. The air pump as claimed in claim 4, with a pressure measurement upper limit value of the pressure gauge less than 30 PSI.
 6. The air pump as claimed in claim 5, with the inflating device including a recess formed in the base, and with a manifold mounted in the recess and forming the passage linearly extending therethrough.
 7. The air pump as claimed in claim 6, with the base including a bottom surface and a top surface spaced from each other, with the bottom surface adapted to be seated on the ground, with the recess extending from the bottom surface to the top surface of the base, and with the pressure gauge mounted on the base and displayed on the top surface.
 8. The air pump as claimed in claim 7, with the protective device received in the detection portion.
 9. The air pump as claimed in claim 7, with the inlet portion and the detection portion respectively disposed on two opposite ends of the top surface of the base and intercommunicated with the recess.
 10. The air pump as claimed in claim 8, with the outlet portion disposed between the inlet portion and the detection portion on the top surface of the base and interconnected with the recess, with the outlet portion connected to a hose, and with an end of the hose opposite to the outlet portion connected to a nozzle.
 11. The air pump as claimed in claim 6, with the pressure gauge engaged in an adapting portion, with a bottom of the adapting portion connected to an extension tube configured to connected with the base, and with the protective device received in the extension tube.
 12. The air pump as claimed in claim 11, with a side of the adapting portion connected with a holding portion, and with the holding portion arranged around a periphery of the cylinder. 